Should I be concerned?

Today at my (29 weeks 4 day) ob checkup and measuring ultrasound, the doctor said baby girl is measuring in 90 percentile, is also measuring 2 weeks ahead, but that her head and torso were larger than her limbs; and that he were not too concerned as of yet but it was something to keep a eye on.. wondering if this is something I should be concerned about, and if so what's it mean??